I'll post pics on all this later:

Last night we broke down a customer's blown motor. There was a GReddy kit installed by another shop and the car was running 9 lbs of boost with the commom upgraded fuel system. There was a lean condition at around 5500 rpm but the motor locked up with no audible warning and *I think* while not under boost.

In the heads there was a broken valve guide on the intake side of number 1. There was no sign of detonation on the pistons (pitting) or broken ringlands, rod #3 sheared almost clean about 1/2 inch below the wrist pin, but piston #3 was undamaged. Piston #1 shredded into a million pieces but the rod was intact with the wrist pin in place. Our diagnosis based on the clean break of rod #3 was that the rod failed and caused the rest of the damage by colliding with piston #1. Our diagnosis was confirmed today by our machinist who also based his opinion on the clean break of rod #3.

2) One of the GReddy manifolds was cracked in a manner consistant with being stressed by the weight of the turbo, downpipe, wastegate and exhaust.

3) We now have Carrillo rods in stock for the 350Z and they are fully 1/3 less weight than the Pauter rods. As soon as our new piston design comes in and our APS shipment gets here the fun will really begin

 

2) Yes, I was concerned about this too...as I know someone else that had this happen with a different kit.

 

Hmm . . . I would like to know more about these rods for my sponsored vehicle With any luck, my car should go under the knife again within the next 2 months (engine build) . . .

Gary

 

Interesting discovery Lorca. Thanks for the insight. I wonder how the engine got leaned out like that?

One thing Lorca. I had the opportunity to dyno my car before and after my Crawford plenum installation. No other changes to A/F ratios were made. With the Crawford plenum, my car was running roughly .5-1.0 A/F points LEANER than with the stock plenum. If no changes were made after installating the Crawford plenum, its possible that a lean condition would exist. Just a thought...and word of caution to anyone that installs the Crawford on an F/I car. I cant remember if Bini had the plenum or not.

Also, were the turbine housing elements damaged by the flying metal everywhere? How about the block and cylinder walls....everything still intact..how about the crank?

 

Typically detonation doesnt cause rods to snap....like you said...you usually see damage to the pistons, rings, and lands.

But if the detonation or even pre-ignition was so fast and instantaneous, you wouldnt see any indications of sustained detonation...just a total destruction of the engine.

Also interesting that that other piston shattered, but the rod was intact...mayeb more signs of pre-ignition?

Lastly, running 9psi on the stock block is very borderline for everyday driving, so catestrophic failure is certainly a possibility.

 

 

 

#3 rod leaning towards #1 cyl

#1 rod intact (you can see #3 on the left)

remnants of #1 piston

#3 piston from the bottom, pretty clean break

closeup

 

top of #3 piston


rods that won't do this at 410rwhp (489 grams)


(655 grams)

 

Wow that is one clean break, do you think it could be sent to a lab for an analysis to see if it was a material defect or anything those guys can find, being in the Atlanta area there should be labs there that do analysis for Delta Airlines. If interested let me know I will find one.

 

amazing photos Lorca....thanks for sharing.

Are the Carillo rods specifically designed for F/I? The Pauter rods are heavier to support high boost applications. They are both quality rods, no question about it, but the Pauter rods will be stronger, given the extra weight and girth...all things being equal (they are both made from Chromoly 4340 forged steel) Those Carillo rods are as light as the Pauter Titanium rods!


Oh, nice pic of the stock piston...definately no signs of prolonged detonation. I think the rods just gave out...they held on for dear life!

 

How long did he run the motor for after it let go???? Looks like quite awhile to get that much metal in the pan.

 

Forgot to post these:

 

The motor locked up and he pulled over, so I don't think there was more than 20-30 seconds. Considering that the motor was probably around 3500rpm, even 20 seconds is more than 1000rpms worth of blender action, more than enough do that to the piston.

I had a similar experience a few years ago with my 300ZX and it was much worse than this. Cruising on the highway at 70 mph, maybe 3500rpm and then a noise that sounded like a tire blow out. 5 rods were snapped, but none as cleanly as this.

 

OMG!!

Thaty has to be the worst engine I have ever seen...

 

These Carrillo's are the same design as the ones we use on most of our high horsepower Z32's. Russell even has them in his 1051rwhp monster. Obviously the Pauter is much beefier and probably stronger. However, keep in mind though is once the rod is strong enough for the application and no longer the weak link in the chain, then you want it to be as light as possible.

The Carrillo's are not going to be the weak link in the VQ, hopefully it will be the headgasket and if its running lean then more likely the forged piston will start to go from prolonged detonation, i.e. broken ringlands, melted top, etc.

 

LOL, thats nothing, you should have seen my Z32

 

Is that manifold cracked through? Or just a surface crack. I am really surprised to see a crack in a cast iron manifold. You normally dont see that.

Either way, is the manifold repairable? Or do you need to get a new one from Greddy?

 

Even the stock cast manifolds on the Z32 will crack although not frequently.

The thing I don't like about the GReddy manifolds is that they have so much weight to support, i.e., turbo, downpipe, huge external wastegate and extra piping. We install inconel tubular manifolds on the Z32 but we always weld a support so the turbo and downpipe doesnt hang on the manifold.

Not sure on the depth, waiting to hear back from GReddy re replacement.

 

Thats a great idea and it would be a tremendous help to us if you coulod locate a facility that would do an analysis that was not cost prohibitive.